CN116380712A - Method for measuring interlayer density of carbon fiber-containing preform material - Google Patents
Method for measuring interlayer density of carbon fiber-containing preform material Download PDFInfo
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- CN116380712A CN116380712A CN202310225162.4A CN202310225162A CN116380712A CN 116380712 A CN116380712 A CN 116380712A CN 202310225162 A CN202310225162 A CN 202310225162A CN 116380712 A CN116380712 A CN 116380712A
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- 229920000049 Carbon (fiber) Polymers 0.000 title claims abstract description 64
- 239000004917 carbon fiber Substances 0.000 title claims abstract description 64
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 63
- 239000000463 material Substances 0.000 title claims abstract description 43
- 239000011229 interlayer Substances 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 27
- 239000010410 layer Substances 0.000 claims abstract description 55
- 239000004744 fabric Substances 0.000 claims abstract description 24
- 238000005498 polishing Methods 0.000 claims abstract description 15
- 230000003287 optical effect Effects 0.000 claims abstract description 10
- 229920005989 resin Polymers 0.000 claims abstract description 5
- 239000011347 resin Substances 0.000 claims abstract description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 17
- 229910052799 carbon Inorganic materials 0.000 claims description 17
- 239000002131 composite material Substances 0.000 claims description 13
- 238000005520 cutting process Methods 0.000 claims description 11
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 claims description 10
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims description 5
- 239000003822 epoxy resin Substances 0.000 claims description 5
- 229920000647 polyepoxide Polymers 0.000 claims description 5
- 244000137852 Petrea volubilis Species 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 229910003460 diamond Inorganic materials 0.000 claims description 4
- 239000010432 diamond Substances 0.000 claims description 4
- 238000010030 laminating Methods 0.000 claims description 4
- 238000005259 measurement Methods 0.000 claims description 4
- 238000007517 polishing process Methods 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 2
- 239000004745 nonwoven fabric Substances 0.000 claims 1
- 238000013461 design Methods 0.000 description 6
- 238000001739 density measurement Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000000879 optical micrograph Methods 0.000 description 2
- 238000010125 resin casting Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/40—Weight reduction
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- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention discloses a measuring method of interlayer density of carbon fiber-containing prefabricated body material, which comprises the steps of embedding a carbon fiber-containing prefabricated body material sample by adopting resin to obtain an embedded sample, sequentially grinding and polishing the surface to be observed of the embedded sample, locally amplifying the surface to be observed of the polished sample by utilizing an optical microscope, measuring the thicknesses of a non-woven cloth layer and a mesh felt layer at different positions, and then measuring the thickness of the non-woven cloth layer and the mesh felt layer at different positions by n=10000/(h) 1 +h 2 ) The invention uses an optical microscope to locally amplify the detected carbon fiber-containing preform material sample, measures and records the thickness of the laid layer and the net tire layer of the sample, and calculates the interlayer density value through the formula of the invention.
Description
Technical Field
The invention belongs to the technical field of composite materials, and particularly relates to a method for measuring interlayer density of a carbon fiber-containing preform material.
Background
The carbon fiber preform is woven from carbon fibers in a certain manner, and has been widely used as a reinforcement for carbon-based composite materials in the fields of aviation, aerospace, automobile industry, medicine, and the like. The interlayer density represents the number of laid layers of the laid cloth or the net-shaped tire in the thickness direction of the carbon fiber preform per centimeter, and the size of the laid cloth or the net-shaped tire is determined by the thickness of the laid cloth and the net-shaped tire. The interlayer density is taken as an important design parameter of the carbon fiber preform structure, and has important influence on the densification rate and the material performance of the carbon fiber reinforced base material.
However, since the thickness of the laid layer and the web layer of the carbon fiber preform are both in the micrometer scale and the resolution therebetween is low, there is still no effective interlayer density measurement method at present. Therefore, how to provide a rapid and accurate method for measuring the interlayer density of the carbon fiber-containing preform material is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a measuring method for the interlayer density of a carbon fiber-containing preform material. The method comprises the steps of locally amplifying a detected carbon fiber preform or carbon fiber reinforced matrix composite sample by using an optical microscope, measuring the thicknesses of a sample laid fabric layer and a net tire layer, and obtaining an interlayer density value through calculation. The invention can accurately measure the interlayer density of the carbon fiber preform and the carbon fiber reinforced matrix composite.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the invention provides a measuring method of interlayer density of carbon fiber-containing precast body material, which comprises the steps of embedding carbon fiber-containing precast body material samples by resin to obtain embedded samples, sequentially grinding and polishing the surface to be observed of the embedded samples, locally amplifying the surface to be observed of the polished samples by using an optical microscope, measuring the thicknesses of a laid fabric layer and a mesh felt layer at different positions, calculating by a formula 1 to obtain the interlayer density,
n＝10000/(h 1 +h 2 ) 1 (1)
Wherein n is the interlayer density, h 1 For the average measurement thickness of the laid layer, h 2 The thickness was measured for the average of the mat layers.
In the present invention, n is in layers/cm; h is a 1 And h 2 In μm.
The invention uses an optical microscope to locally amplify the detected carbon fiber-containing preform material sample, and measures and records the thickness of the laid layer and the net tire layer of the sampleDegree, then using the formula n=10000/(h) provided by the present invention 1 +h 2 ) The interlayer density value is obtained through calculation.
Preferably, the carbon fiber-containing preform material is selected from one of a carbon fiber preform, a carbon/carbon composite material and a carbon ceramic composite material.
In a preferred scheme, the prefabricated body structure in the carbon fiber-containing prefabricated body material is formed by alternately laminating and laying laid weftless fabrics and net tires, and needling or puncturing between layers.
In a preferred embodiment, the carbon fiber-containing preform material sample is obtained by cutting a carbon fiber-containing preform material by an automatic wire cutting machine. The automatic wire cutting machine can avoid deformation in the cutting process of the carbon fiber preform sample, change the thickness of the laid fabric layer and the net tire layer, and finally influence the accuracy of the test result.
In a preferred embodiment, the carbon fiber-containing preform material sample has a length-width of (5-25) mm (10-25) mm (3-25) mm, wherein the length-height plane is the plane to be observed.
Preferably, the surface to be observed of the carbon fiber-containing prefabricated body material sample is perpendicular to the laid layer plane of the laid cloth.
In a preferred scheme, the process of inlaying the carbon fiber-containing preform material sample by adopting resin comprises the following steps: placing a carbon fiber-containing preform material sample in a mold, pouring by adopting a cold insert, and solidifying under a vacuum condition to obtain the carbon fiber-containing preform material sample;
the cold insert is prepared from epoxy resin, dibutyl phthalate and ethylenediamine according to the mass ratio of (80-120): (18-22): (5-10) and is prepared by modulation.
Further preferably, the cold insert is prepared from epoxy resin, dibutyl phthalate and ethylenediamine according to the mass ratio of (95-105): (19-21): (6-8) and is prepared by modulation.
Further preferably, the curing temperature is 30 ℃ to 50 ℃, preferably 38 ℃ to 42 ℃.
Preferably, the grinding process is as follows: and sequentially carrying out rough grinding, fine grinding and fine grinding by using 200 CW-1500 CW sand paper.
Preferably, the polishing process is performed sequentially by using a polishing fabric and a diamond polishing agent of 1.5-3.0 μm.
The inventor finds that the thickness of the laid fabric layer and the felt layer can be clearly measured in an optical microscope by adopting the cold insert formula and the surface to be observed prepared in the grinding and polishing processes.
Preferably, the surface to be observed of the polished sample is locally magnified 10 to 100 times, preferably 20 to 50 times, by an optical microscope.
In the preferred scheme, the thicknesses of the non-woven layers and the mesh felt layers at different positions are measured to obtain N groups of data, wherein N is more than or equal to 10, and each group of data comprises 1-3 data. Sampling data should be as large as possible, and too small a sample size may result in a large error in the interlayer density measurement.
The invention has the following beneficial effects:
the invention uses an optical microscope to locally amplify the detected carbon fiber-containing precast body material sample, measures and records the thickness of the laid layer and the net tire layer of the sample, and calculates the interlayer density value through the formula of the invention.
Drawings
FIG. 1 is an optical micrograph of a sample of the carbon fiber preform of example 1;
fig. 2 is an optical micrograph of a carbon/carbon composite sample of example 2.
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present application, the present application will be clearly and completely described in connection with specific embodiments, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, shall fall within the scope of the present application.
Example 1
a. Preparing a carbon fiber preform with a needling structure to be detected, wherein the preform is formed by alternately laminating a layer of PANCF laid fabric and a layer of PANCF net tire through continuous needling, and the adjacent laid fabric layers are 0 DEG/90 DEG layers. The interlayer density design value of the carbon fiber preform is 15+/-1 layers/cm, and the factory report value of the factory is 15.6 layers/cm;
b. cutting the carbon fiber preform into a sample with a width of 20mm by 10mm by using an automatic wire cutting machine;
c. the cut sample is subjected to sample insertion by adopting a resin casting cold insert method, wherein epoxy resin, dibutyl phthalate and ethylenediamine are mixed according to the following ratio of 95:20:6, modulating the mass ratio; then curing in a vacuum heating drying oven at a temperature of 42 ℃;
d. rough grinding, fine grinding and fine grinding are respectively carried out on the surface to be observed of the sample on a grinding/polishing machine by using sand paper of 280CW, 600CW and 1000 CW; polishing the ground surface to be observed by using a polishing fabric and a 2um diamond polishing agent;
e. locally amplifying the surface to be observed of the sample by 50 times by using a metallographic microscope, measuring the thickness of the laid fabric layer and the felt layer at different positions of the sample (shown in figure 1), and recording 20 groups of measurement data, wherein the table 1 is shown;
f. according to the interlayer density calculation formula n=10000/(h) 1 +h 2 ) The interlayer density of the sample can be calculated to be 14.9 layers/cm, which is equivalent to a factory report value of a preform manufacturer, and the interlayer density of the carbon fiber preform can be accurately and effectively measured within a design range value.
TABLE 1
Example 2
a. A carbon/carbon composite material is prepared, wherein the carbon/carbon composite material is formed by densifying a carbon fiber preform through chemical vapor deposition, and the preform is formed by alternately laminating a layer of PANCF laid fabric and a layer of PANCF net tire, and layering adjacent laid fabric layers at 0 degrees/90 degrees, and continuously needling. The interlayer density design value of the preform is 21+/-1 layers/cm, and the factory report value of the manufacturer is 21.1 layers/cm;
b. cutting the carbon/carbon composite material into test pieces with 50mm x 10mm x 20mm wide x height by using a wire cutting machine;
c. the cut sample is subjected to sample insertion by adopting a resin casting cold insert method, wherein the epoxy resin, dibutyl phthalate and ethylenediamine are mixed according to the weight ratio of 100:20:7, modulating the mass ratio; then curing in a vacuum heating drying oven at 40 ℃;
d. rough grinding, fine grinding and fine grinding are respectively carried out on the surface to be observed of the sample on a grinding/polishing machine by using sand paper of 280CW, 600CW and 1000 CW; polishing the ground surface to be observed by using a polishing fabric and a 2um diamond polishing agent;
e. locally amplifying the surface to be observed of the sample by 25 times by using a metallographic microscope, measuring the thickness of the laid fabric layer and the felt layer at different positions of the sample (shown in figure 2), and recording 20 groups of measurement data, wherein the table 2 is shown;
f. according to the interlayer density calculation formula n=10000/(h) 1 +h 2 ) The interlayer density of the sample can be calculated to be 22.2 layers/cm, and is relatively close to a factory report value and a design range value of a preform manufacturer, and the method can accurately and effectively measure the interlayer density of the carbon/carbon composite material.
TABLE 2
Comparative example 1
The carbon fiber preform structure and other processes were the same as in example 1 except that the carbon fiber preform was cut using a manual cutter during step b. The original structure of the carbon fiber preform is changed in a manual cutting mode, the thickness measured value of the final laid fabric layer is 356 mu m, the thickness measured value of the net tire layer is 382 mu m, the interlayer density of the sample obtained by calculation according to the formula 1 is 13.5 layers/cm, the interlayer density exceeds the design value range of the interlayer density of the carbon fiber preform, and the deviation from a factory report value of a preform manufacturer is large.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method for measuring the interlayer density of a carbon fiber-containing preform material, characterized by: embedding the carbon fiber-containing preform material sample with resin to obtain an embedded sample, sequentially grinding and polishing the surface to be observed of the embedded sample, locally amplifying the surface to be observed of the polished sample by using an optical microscope, measuring the thicknesses of the non-woven fabric layer and the mesh felt layer at different positions, calculating by a formula 1 to obtain the interlayer density,
n＝10000/(h 1 +h 2 ) 1 (1)
Wherein n is the interlayer density, h 1 For the average measurement thickness of the laid layer, h 2 The thickness was measured for the average of the mat layers.
2. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: the carbon fiber-containing preform material is selected from one of a carbon fiber preform, a carbon/carbon composite material and a carbon ceramic composite material.
3. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: the prefabricated body structure in the carbon fiber-containing prefabricated body material is formed by alternately laminating and laying laid weftless fabrics and net tires, and needling or puncturing is carried out between the layers.
4. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: the carbon fiber-containing prefabricated body material sample is obtained by cutting the carbon fiber-containing prefabricated body material through an automatic wire cutting machine.
5. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: the carbon fiber-containing preform material sample has a size of (5-25) mm (10-25) mm (3-25) mm long by height and width, wherein the long by height surface is the surface to be observed.
6. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: the surface to be observed of the carbon fiber-containing prefabricated body material sample is perpendicular to the laid plane of the laid cloth.
7. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: the process for embedding the carbon fiber-containing preform material sample by adopting resin comprises the following steps: placing a carbon fiber-containing preform material sample in a mold, pouring by adopting a cold insert, and solidifying under a vacuum condition to obtain the carbon fiber-containing preform material sample;
the cold insert is prepared from epoxy resin, dibutyl phthalate and ethylenediamine according to the mass ratio of (80-120): (18-22): (5-10) modulating;
the curing temperature is 30-50 ℃.
8. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: the grinding process comprises the following steps: sequentially carrying out rough grinding, fine grinding and fine grinding by using 200 CW-1500 CW sand paper;
the polishing process is carried out by using a polishing fabric and a diamond polishing agent with the diameter of 1.5-3.0 mu m in sequence.
9. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: and locally magnifying the surface to be observed of the polished sample by using an optical microscope by 10-100 times.
10. The method for measuring the interlayer density of a carbon fiber-containing preform material according to claim 1, wherein: and measuring the thicknesses of the non-woven layers and the felt layers at different positions to obtain N groups of data, wherein N is more than or equal to 10, and each group of data comprises 1-3 data.
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| CN202310225162.4A CN116380712A (en) | 2023-03-10 | 2023-03-10 | Method for measuring interlayer density of carbon fiber-containing preform material |
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| CN202310225162.4A CN116380712A (en) | 2023-03-10 | 2023-03-10 | Method for measuring interlayer density of carbon fiber-containing preform material |
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| CN202310225162.4A Pending CN116380712A (en) | 2023-03-10 | 2023-03-10 | Method for measuring interlayer density of carbon fiber-containing preform material |
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